The invention relates to a gas generator, in particular for belt tighteners.
Pressure elements for use in belt tighteners of motor vehicles are known from DE 43 07 774 A1. Buckle tighteners or belt-roller winders are generally understood by the term belt tighteners. These pressure elements, called gas generators in the following, consist of a housing in which are arranged, inter alia, a propellent charge for generating a pressure gas and an igniter. In addition, in order to improve the ignition, it is also possible to provide a propagation charge between the igniter and propellent charge. The igniter or igniting element is provided with a socket. The housing embraces this socket or an additional portion and presses it in a sealing manner against the housing wall. A plug is plugged into the socket from the outside for the purposes of electrical coupling. Thus, the igniter is electrically connected by way of the plug to a control unit located outside the gas generator.
It is also known to integrate in the plug a form of protection against electromagnetic action.
A disadvantage of this pressure element or gas generator is the comparatively great outlay that is required for its assembly. The use of a socket/plug combination limits the minimum diameter of the gas generator.
The underlying object of the invention is to develop further a gas generator in such a way that it can be produced with a small diameter.
According to the invention this object is achieved
by having the electrical coupling take place by way of connecting wires, or pins, or cables which are inserted into the housing by way of a stopper and which are sealed by the latter, and
by having the stopper surrounded in a sealing manner by the housing itself or by a holding element which is connected to the housing in a sealing manner.
The use of connecting wires or pins, or cables, which are inserted into the interior of the housing by way of a stopper, substantially simplifies the sealing of the gas generator, since the stopper is, at the same time, used for sealing purposes.
The stopper preferably consists of a synthetic rubber or plastics material. Examples of materials are styrene-butadiene-rubber (SBR), acrylonitrile rubber (NBR) or fluorinated rubber (FPM). The connection of the stopper with the housing is effected by suitable measures, such as crimping, adhesion or potting. Crimping has proved to be particularly advantageous.
The stopper is preferably pushed, sprayed or vulcanized onto the connecting wires or pins or the cable.
Advantageously, electronic components or a printed circuit board can be arranged in the interior of the housing as connecting elements or as a connecting element between the igniter and the connecting wires or pins. Suitable electronic components or active or passive circuit arrangements can be arranged on the printed circuit board in order to bring about protection against electromagnetic action. Likewise, the electronic connecting element can be formed as a switch or a safety element.
In an alternative advantageous embodiment, the igniter is directly connected to the connecting wires or pins. In this connection it is advantageous to integrate a form of protection against electromagnetic action and/or a switch and/or a safety element in the igniter.
The type of or the form of the igniter is not pre-set. Ignition caps are best suited to each case. Ignition caps in bar form or with a copper-clad pole body, which can be used to accommodate electronic components, are preferred. Ignition caps are described in DE 42 36 729 A1, for example.
To protect against electrostatic phenomena, the housing advantageously has an inwardly directed channel formation in the area of the electrical supply lines as a desired spark gap. The igniter is advantageously embedded in an insulating sleeve or in a protective tube. In addition to protecting the igniting material from electrostatic discharges, in this way no damage as a result of vibrations results at the igniter. This applies especially to ignition caps.
In order to be able to configure the guiding of the connecting wires or pins or the cable in a variable manner, in a preferred embodiment a cable guide is arranged at the end face of the gas generator at which the connecting wires or pins or the cable are inserted. This cable guide is advantageously sprayed thereon or fusion-cast.
Furthermore, the housing suitably has predetermined breaking points either on the base or on the housing wall.